Please include "Aliens" as a tag. That's interesting too!
I think you may be misunderstanding the workings of Area51, or your terminology is a bit off.
The main purpose of Area51 is to propose new sites. These proposals fall into one of a few categories (art, business, culture, etc., see the left-hand column of the main page)
Questions are about Area51 itself, or a specific (existing) proposal. Tags are added to questions. In this context, an "Aliens" tag won't really make sense.
If you meant an Aliens proposal, note that there is already one.